feat: provide removeTwoslashNotations fallback function

packages/twoslash/build.config.ts

@@ -4,6 +4,7 @@ export default defineBuildConfig({
   entries: [
     'src/index',
     'src/core',
+    'src/fallback',
   ],
   declaration: true,
   clean: true,

packages/twoslash/package.json

@@ -22,11 +22,22 @@
     "./core": {
       "import": "./dist/core.mjs",
       "require": "./dist/core.cjs"
+    },
+    "./fallback": {
+      "import": "./dist/fallback.mjs",
+      "require": "./dist/fallback.cjs"
     }
   },
   "main": "dist/index.mjs",
   "module": "dist/index.mjs",
   "types": "dist/index.d.mts",
+  "typesVersions": {
+    "*": {
+      "./core": ["./dist/core.d.mts"],
+      "./fallback": ["./dist/fallback.d.mts"],
+      "*": ["./dist/index.d.mts"]
+    }
+  },
   "files": [
     "dist"
   ],

packages/twoslash/scripts/flag-keys.ts

@@ -0,0 +1,17 @@
+import fs from 'node:fs/promises'
+import ts from 'typescript'
+import type { CompilerOptionDeclaration } from '../src/types/options'
+import { defaultHandbookOptions } from '../src/defaults'
+
+async function generateFlagKeys() {
+  const tsOptionDeclarations = (ts as any).optionDeclarations as CompilerOptionDeclaration[]
+
+  const keys = [
+    ...tsOptionDeclarations.map(i => i.name),
+    ...Object.keys(defaultHandbookOptions),
+  ].sort()
+
+  await fs.writeFile('src/flag-keys.ts', `// Generated by scripts/flag-keys.ts\nexport const flagKeys = ${JSON.stringify(keys, null, 2)}`, 'utf-8')
+}
+
+generateFlagKeys()

packages/twoslash/src/core.ts

@@ -134,7 +134,7 @@ export function createTwoslasher(createOptions: CreateTwoslashOptions = {}): Two
     const pc = createPositionConverter(code)
 
     // extract cuts
-    meta.removals.push(...findCutNotations(code))
+    findCutNotations(code, meta)
     // extract markers
     findQueryMarkers(code, meta, pc)
 

packages/twoslash/src/fallback.ts

@@ -0,0 +1,40 @@
+import { removeCodeRanges } from 'twoslash-protocol'
+import { reAnnonateMarkers, reConfigBoolean, reConfigValue } from './regexp'
+import type { TwoslashReturnMeta } from './types'
+import { findCutNotations } from './utils'
+import { flagKeys } from './flag-keys'
+
+/**
+ * A fallback function to strip out twoslash annotations from a string and does nothing else.
+ *
+ * This function does not returns the meta information about the removals.
+ * It's designed to be used as a fallback when Twoslash fails.
+ */
+export function removeTwoslashNotations(code: string, customTags?: string[]): string {
+  const meta: Pick<TwoslashReturnMeta, 'removals'> = {
+    removals: [],
+  }
+  const tags = [
+    ...customTags ?? [],
+    ...flagKeys,
+  ]
+
+  Array.from(code.matchAll(reConfigBoolean)).forEach((match) => {
+    if (!tags.includes(match[1]))
+      return
+    meta.removals.push([match.index!, match.index! + match[0].length + 1])
+  })
+  Array.from(code.matchAll(reConfigValue)).forEach((match) => {
+    if (!tags.includes(match[1]))
+      return
+    meta.removals.push([match.index!, match.index! + match[0].length + 1])
+  })
+
+  findCutNotations(code, meta)
+  Array.from(code.matchAll(reAnnonateMarkers)).forEach((match) => {
+    const index = match.index!
+    meta.removals.push([index, index + match[0].length + 1])
+  })
+
+  return removeCodeRanges(code, meta.removals).code
+}

packages/twoslash/src/flag-keys.ts

@@ -0,0 +1,132 @@
+// Generated by scripts/flag-keys.ts
+export const flagKeys = [
+  'all',
+  'allowArbitraryExtensions',
+  'allowImportingTsExtensions',
+  'allowJs',
+  'allowSyntheticDefaultImports',
+  'allowUmdGlobalAccess',
+  'allowUnreachableCode',
+  'allowUnusedLabels',
+  'alwaysStrict',
+  'assumeChangesOnlyAffectDirectDependencies',
+  'baseUrl',
+  'build',
+  'charset',
+  'checkJs',
+  'composite',
+  'customConditions',
+  'declaration',
+  'declarationDir',
+  'declarationMap',
+  'diagnostics',
+  'disableReferencedProjectLoad',
+  'disableSizeLimit',
+  'disableSolutionSearching',
+  'disableSourceOfProjectReferenceRedirect',
+  'downlevelIteration',
+  'emitBOM',
+  'emitDeclarationOnly',
+  'emitDecoratorMetadata',
+  'errors',
+  'esModuleInterop',
+  'exactOptionalPropertyTypes',
+  'experimentalDecorators',
+  'explainFiles',
+  'extendedDiagnostics',
+  'forceConsistentCasingInFileNames',
+  'generateCpuProfile',
+  'generateTrace',
+  'help',
+  'help',
+  'ignoreDeprecations',
+  'importHelpers',
+  'importsNotUsedAsValues',
+  'incremental',
+  'init',
+  'inlineSourceMap',
+  'inlineSources',
+  'isolatedModules',
+  'jsx',
+  'jsxFactory',
+  'jsxFragmentFactory',
+  'jsxImportSource',
+  'keepNotations',
+  'keyofStringsOnly',
+  'lib',
+  'listEmittedFiles',
+  'listFiles',
+  'listFilesOnly',
+  'locale',
+  'mapRoot',
+  'maxNodeModuleJsDepth',
+  'module',
+  'moduleDetection',
+  'moduleResolution',
+  'moduleSuffixes',
+  'newLine',
+  'noEmit',
+  'noEmitHelpers',
+  'noEmitOnError',
+  'noErrorTruncation',
+  'noErrorValidation',
+  'noErrors',
+  'noErrorsCutted',
+  'noFallthroughCasesInSwitch',
+  'noImplicitAny',
+  'noImplicitOverride',
+  'noImplicitReturns',
+  'noImplicitThis',
+  'noImplicitUseStrict',
+  'noLib',
+  'noPropertyAccessFromIndexSignature',
+  'noResolve',
+  'noStaticSemanticInfo',
+  'noStrictGenericChecks',
+  'noUncheckedIndexedAccess',
+  'noUnusedLocals',
+  'noUnusedParameters',
+  'out',
+  'outDir',
+  'outFile',
+  'paths',
+  'plugins',
+  'preserveConstEnums',
+  'preserveSymlinks',
+  'preserveValueImports',
+  'preserveWatchOutput',
+  'pretty',
+  'project',
+  'reactNamespace',
+  'removeComments',
+  'resolveJsonModule',
+  'resolvePackageJsonExports',
+  'resolvePackageJsonImports',
+  'rootDir',
+  'rootDirs',
+  'showConfig',
+  'showEmit',
+  'showEmittedFile',
+  'skipDefaultLibCheck',
+  'skipLibCheck',
+  'sourceMap',
+  'sourceRoot',
+  'strict',
+  'strictBindCallApply',
+  'strictFunctionTypes',
+  'strictNullChecks',
+  'strictPropertyInitialization',
+  'stripInternal',
+  'suppressExcessPropertyErrors',
+  'suppressImplicitAnyIndexErrors',
+  'target',
+  'traceResolution',
+  'tsBuildInfoFile',
+  'typeRoots',
+  'types',
+  'useDefineForClassFields',
+  'useUnknownInCatchVariables',
+  'verbatimModuleSyntax',
+  'version',
+  'watch',
+]

packages/twoslash/src/public.ts

@@ -11,6 +11,10 @@ export {
   getObjectHash,
 } from './utils'
 
+export {
+  removeTwoslashNotations,
+} from './fallback'
+
 export {
   validateCodeForErrors,
 } from './validation'

packages/twoslash/src/utils.ts

@@ -253,7 +253,7 @@ export function findFlagNotations(code: string, customTags: string[], tsOptionDe
   return flagNotations
 }
 
-export function findCutNotations(code: string) {
+export function findCutNotations(code: string, meta: Pick<TwoslashReturnMeta, 'removals'>) {
   const removals: Range[] = []
 
   const cutBefore = [...code.matchAll(reCutBefore)]
@@ -288,6 +288,10 @@ export function findCutNotations(code: string) {
     }
     removals.push([start.index!, end.index! + end[0].length + 1])
   }
+
+  if (meta)
+    meta.removals.push(...removals)
+
   return removals
 }
 

packages/twoslash/test/fixtures.test.ts

@@ -4,7 +4,7 @@ import { extname } from 'node:path'
 import process from 'node:process'
 import { expect, it } from 'vitest'
 import type { TwoslashReturn } from '../src/types'
-import { createTwoslasher } from '../src/index'
+import { createTwoslasher, removeTwoslashNotations } from '../src/index'
 
 // To add a test, create a file in the fixtures folder and it will will run through
 // as though it was the codeblock.
@@ -32,9 +32,10 @@ Object.entries(fixtures).forEach(([path, fixture]) => {
     path,
     async () => {
       let result: TwoslashReturn = undefined!
+      const code = await fixture()
       try {
         result = twoslasher(
-          await fixture(),
+          code,
           inExt,
           {
             customTags: ['annotate'],
@@ -58,6 +59,11 @@ Object.entries(fixtures).forEach(([path, fixture]) => {
       else {
         expect(cleanFixture(result))
           .toMatchFileSnapshot(outPath)
+
+        if (!result.meta.handbookOptions.showEmit) {
+          expect(removeTwoslashNotations(code))
+            .toEqual(result.code)
+        }
       }
     },
   )